Archiv článků od 31.8.2015 do 2.10.2017

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Otázky sanací betonových konstrukcí parkovacích a garážových objektů

Questions of Rehabilitation a Concrete Construction of Parking Buildings

2.10.2017 | Ing. Vítězslav Vacek, CSc., doc. ing. Jiří Kolísko, Ph.D., ČVUT Praha. Kloknerův ústav
The article deals with the possibilities of rehabilitation of concrete structures the technical and technological aspects in relation to the detected condition, execute, operate and its age.
Kompozitní výztuž do betonu

Concrete and reinforced concrete

18.9.2017 | Ing. Miroslav Procházka, Technický a zkušební ústav stavební Praha, s.p.
The composite materials for strengthening/reinforcement a concrete has become the new construction product set up for compulsory verification pursuant to Act No. 22/1997 Coll. (č. 22/1997 Sb.) as amended by Government Ordinance No. 163/2002 Coll. (č. 163/2002 Sb.) as amended by Government Decree No. 312/2005 Coll. and No. 215/2016 Coll (č. 312/2005 Sb. a č. 215/2016 Sb.) This reinforcement exists in several different types, and accordingly, it also has significantly different properties which must be strictly respected in its use.

Technology of Excavated Soil and its Liquefaction with the Addition of Fly Ash

4.9.2017 | Ing. Magdaléna Kociánová, Ing. Vít Černý , Ph.D., prof. ing. Rostislav Drochytka, CSc., MBA, VUT FAST Brno
The paper describes the technology of liquefaction and stabilization of soils that are created in the excavation works of engineering networks. Liquefied grout could be used to fill even the less accessible spaces of utility networks. For the re-use of the excavated soil in a liquefied form, is necessary its pre-treatment, which consists in stabilizing by the suitable stabilizing additive. The mixture is furthermore required the liquefaction by using a suitable liquefying additives. Suitable for stabilization and soil liquefaction it seems the use of fly ash, as is mentioned below in the paper.

Dehumidfication of the Massonry by Microwave Radiation in the Practice

26.6.2017 | Ing. Kamil Binek, doc. Ing. Juraj Žilinský, PhD., Slovenská technická univerzita v Bratislave, Stavebná fakulta, Katedra konštrukcií pozemných stavieb
The cause of moisture in the masonry could by different. By old historical buildings is the problem in absence of hydro-insulation, which was made by flat stones or clay backfill. New buildings have a lot defect by application (for example: pipes penetration, join) or wrong design of hydro-insulation, which are the point infiltration of water in to the construction. This problems are made by wrong projection of hydro-insulation in the project. The project does not reflect all influences of the water. But they are also another cases, which can happened like river floods, flood by the neighbour. In those cases it is demanding to dry the building as soon as possible, to protect the property from the mold and return the function of the building. One of the method, which is suitable for this solution is microwave dehumidification, which realize all conditions in one. This aim include also the practice example of the microwave sanitation technique, used by dehumidification masonry, and the positive results.
Bytové domy v Praze © TZB-info

What are the common parts of residential buildings in the Czech Republic?

19.6.2017 | Ing. Petr Bohuslávek, redakce
The definition of what is a common part of a residential building is essential especially when modifying the building structures and eliminating defects that affect both a common part and residential units. How common parts are defined affects who finances the modifications and reconstructions of such structures and parts. The definition of common parts is based on the new Civil Code (No. 89/2012 Coll.) and on the already abolished Act on Ownership of Housing (No. 72/1994 Coll.).
tesařské spoje © martinfredy - Fotolia.com

Current Issue of Carpentry Joints Structural Designing

5.6.2017 | Ing. Martin Hataj, doc. Ing. Petr Kuklík, CSc., ČVUT v Praze, pracoviště UCEEB
A growing environmental awareness and desire for sustainable solutions and healthy living conditions, especially in Europe, lead to an increasing demand for timber structures. High speed, excellent cut quality and accuracy of CNC processing allows an effective produce of timber structures by traditional carpentry procedures. This article responds to current problem of load bearing capacity calculations of traditional carpentry joints. This way of structural joints has not sufficient support in current standards and therefore design relies on simple empirical relationships based on experience. This paper presents the experimental and calculation methods for investigation of static behaviour and load bearing capacity of carpentry joints.

Securing brick buildings against the influence of technical seismicity

29.5.2017 | doc. Ing. Jaroslav Solař, Ph.D., VŠB TU Ostrava
The contribution dealst with the problematics of statical defects, or more precisely with the formation of cracks in the brickwork caused by the effect of technical seismicity. It further deals with the construction principles which can be used when designing reconstruction of buildings which are located within the reach of the effect of technical seimicity. The problematics of historical buildings and conservation areas is also mentioned.

Thermal-technical evaluation of inner wall cavities within framework of a suggestion of wet masonry rehabilitation

22.5.2017 | doc. Ing. Jaroslav Solař, Ph.D., VŠB TU Ostrava
For excessive wet masonry rehabilitation, except for other methods, the method of air cavities is used. These can be wall or floor cavities. The wall cavities may be situated either on the internal or the external side of the wall. From the height point of view, internal side cavities can be located under the floor or above the floor level. This contribution only deals with the cavities above the floor level. In the projection practice, the air cavities usually are designed only empirically. But it is necessary to carry out their thermal-technical evaluation for their correct capacity. The matter of the evaluation is the topic of the following contribution.
2 comments, last 29.08.2017 08:03
sklad dřeva © industrieblick - Fotolia.com

Pore size distribution by mercury intrusion porosimetry

8.5.2017 | Ing. Martin Keppert, Ph.D., Univerzitní centrum energeticky efektivních budov (UCEEB) při ČVUT v Praze
The papers aims to illustrate possibility to characterize pore system of wood and to quantify its pore size distribution by mercury intrusion porosimetry as simple and fast experimental method.

Evaluation of Material Properties of Fibre-reinforced Concrete

27.3.2017 | prof. Ing. Leonard Hobst, CSc., Ústav stavebního zkušebnictví VUT Brno, prof. Ing. Jiří Vala, CSc., Ústav matematiky a deskriptivní geometrie VUT Brno
Long-time study of fibre-reinforced concrete, i.e. a composite material with a cementitious matrix, whose structure is hardened by usually randomly distributed fibres (steel ones in the most frequent case), demonstrates good mechanical and other technical properties, which makes possible its utilization in bearing structures. This stimulates the development of methods, non-destructive or low-invasive if possible, for the analysis of its structure, which determines crucial mechanical properties, e.g. fracture resistance under tensile loads. This article, coming from research activities of the Faculty of Civil Engineering at Brno University o Technology, brings an overview of available methods, namely direct methods coming from image processing and indirect ones utilizing measurements of electromagnetic quantities.
1 comment, 27.03.2017 11:54

The invention, patent or utility model - who should sort?

8.3.2017 | Ing. Zdeněk Lyčka
The article explains the differences between the invention patents and utility model from the perspective of Czech legislation. Also highlights the confusion individual categories and purposeful fraud by producers and sellers of equipment.
1 comment, 08.03.2017 07:44

Measurement and Evaluation of the Significant Sources of Natural Radioactivity

6.3.2017 | prof. Ing. Leonard Hobst , CSc., VUT v Brně
The natural radioactivity lives mankind throughout its development. The effects of radiation to some extent they can influence the evolutionary history of life on Earth. It is therefore important to determine what values the natural radioactivity would reach different locations of the world.

Floor area in living spaces with slanting ceilings

20.6.2016 | Josef Remeš, Ing. et Ing. Petr Hlavsa, Ing. Radim Kolář, Ph.D., Fakulta stavební VUT v Brně
Floor area in living spaces with slanting ceilings has an ambiguous interpretion in czech national regulations. It has an effect on a building approval process and this article describes how to determine this area in both architecture and civil enginnering.
1 comment, 21.06.2016 11:21

Experimental study of influence of nanomaterials on photocatalytic properties of concrete

9.5.2016 | Ing. Petr Bílý, Ing. Josef Fládr, Fakulta stavební ČVUT v Praze, Katedra betonových a zděných konstrukc
The study is focused on evaluation of titanium dioxide nanoparticles (N-TiO2) impact on photocatalytic properties of concrete surface. Specimens made from ordinary white cement with no TiO2 particles, specimens made from commercially available photocatalytic cement and specimens made from white cement covered with polyvinyl alcohol (PVA) nanotextile containing N-TiO2 were compared with respect to their ability to decompose rhodamine B dye when exposed to direct UV radiation. PVA nanotextile was prepared by electrospinning method. The solution exploiting the nanotextile was not found to be prospective in this phase of the research. However, the method of preparation of enriched nanotextiles as well as their application on the surface of concrete elements was tried and can be adjusted for different purposes.

Production, properties and utilization of pulp from Miscanthus sinensis

8.2.2016 | Ing. Michal Frank, Výzkumný ústav stavebních hmot Brno (VUSTAH), Ing. Jan Gojný, Ph.D., Fakulta chemicko-technologická, Univerzita Pardubice
The article describes use of Miscanthus sinensis for a manufacturing of pulp. Miscanthus sinensis is a perennial plant, its cultivating is easy and it can be used for various purposes.
In the first phase of the pulp preparation from Miscanthus, a laboratory preparation of pulp was done at the University of Pardubice in total amount of 6 individual batches. In the second phase a selected laboratory batch was prepared in a pilot production process and ca. 2000 g of pulp in total was generated for further tests.
Mechanical properties and also other properties typical for pulp were determined on prepared samples. The produced pulp was used in the next step for a preparation of fibre-cement boards. Their basic physico-mechanical parameters were also determined.
After evaluation of all data that we have, production of 500 kg of pulp was done. Then the pulp was used to produce fibre-cement boards in a mass production.

Air permeation rate of oriented strand boards depending on the type and thickness of the board

25.1.2016 | Ing. Matěj Hodoušek, doc. Ing. Martin Böhm, Ph.D., Ing. Jitka Beránková, Ph.D., Výzkumný a vývojový ústav dřevařský, Praha s.p., Ing. Jaromír Srba, Katedra dřevěných výrobků a konstrukcí, Fakulta lesnická a dřevařská, Česká zemědělská univerzita v Praze
In this research study we analyzed air permeation rate of oriented strand boards, OSB/3 and OSB/4 according to the ČSN EN 12114. OSB boards were manufactured in accordance with the ČSN EN 300 in the Czech Republic. We evaluated the influence of the board thickness (for the most used board thickness 12 and 18 mm) and the influence of the board type (OSB/3 and OSB/4) on air permeation rate values. We have proved that the groups of OSB/3 samples show lower resistance to air permeability than OSB/4. Furthermore 18 mm thick samples at both board types show higher resistance to air permeability than 12 mm thick samples.
3 comments, last 29.01.2016 12:48

Shear adhesive connections for glass structures

11.1.2016 | Ing. Klára Machalická, Ph.D., Ing. Iva Pravdová, doc. Ing. Martina Eliášová, CSc., ČVUT Praha
Transparency and also smooth, glossy and reflective glass surface give special importance of this material in the contemporary architecture. Connections between two glass elements or glass pane and other part from a different material are very important issue for structural applications of glass. Moreover, there are many types of hybrid structures that combine glass and different materials to achieve safe failure behaviour and high degree of transparency at the same time. Connection of brittle glass and reinforcing material is an essential part of these structures, where composite action between two parts is beneficially ensured by a glued joint. Experimental determination of mechanical characteristics of various adhesives applied in planar connections under shear loading is a main topic of current paper.

Redevelopment of industrial concrete floors after the fire hall

16.11.2015 | Ing. Karel Mikulica, prof. Ing. Rudolf Hela, CSc., Ústav technologie stavebních hmot a dílců, FAST VUT v Brně
Concrete exposed to high temperature considerably changes its properties down to total destruction. The paper describes renovation of concrete floor damaged by a fire of a factory building. Individual steps of determination of damage of concrete floor structures caused by high temperatures are described. Structure of damaged floor was technically analyzed, redevelopment was designed and renovation works were carried out.

Tropical woods – their advantages and problems while using

19.10.2015 | Ing. Miloš Pánek, Ph.D., Fakulta lesnická a dřevařská ČZU v Praze
This article deals about tropical hardwood species used for commercial purposes. These kinds of wood have more advantages like better natural durability against bio-degradation caused by high amount of extractives and good mechanical and physical properties. But their using is also connected with some questions – ecological and economical aspects and stability of supposed properties for each delivery. Not solved problem is protection against weathering and mainly decreasing of colour changes of tropical wood surfaces in the exterior till now.

FLOOR SPACE IN FACILITY MANAGEMENT

31.8.2015 | Ing. Petra Okřinová, Ing. Josef Remeš, Vysoké učení technické v Brně, Fakulta stavební, Ústav automatizace inženýrských úloh a informatiky
The article describes floor surfaces and form of their determination in construction and other fields, such as services, real estate, valuation, facility management and more. In Europe, each country has a different technical standard. This means that when we are determining the type of floor area for buildings with these technical standards, we can conclude that they differ by up to 30 %. Therefore, we chose a sample idea of building on which we symbolized each floor type. We tried to make clear, which constructions and types of floor are creditable and which are not. To demonstrate the importance of correct identification of floor surface we give an example calculation of cleaning services where savings could be seen in the correct determination of the floor surface.
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